Calcium and Magnesium may form abrasive solids or be present as soluble metallic soaps. If present as solids, excessive injector, fuel pump, piston, and ring wear may result. Soluble metallic soaps may contribute to filter plugging and engine deposits. High levels of these elements may accumulate in exhaust particulate removal devices and may increase back pressure that may require shorter maintenance intervals. Calcium and Magnesium analysis is performed in accordance with EN 14538.
ASTM D6751 Requirement: a maximum of 5ppm (wt/wt) combined calcium and magnesium content.